Wendy asked about undescended testicles:

AFAIK, no. I did find the following from:
http://www.ivis.org/advances/Concannon/memon/chapter_frm.asp?LA=1

Visual examination and careful digital palpation of the scrotum and
inguinal area is helpful. However, scrotal fat and inguinal lymph nodes
may be confused with the retained testis. Abdominal testes are difficult
to palpate or visualized by ultrasonography (US). The use of human
Chorionic Gonadotrophin (hCG) or Gonadotropin Releasing Hormone (GnRH)
Stimulation Test for inducing a measurable testosterone increase is
recommended. Commercial bovine GnRH products, Cystorelin ® or Factrel
® may be used. The standard protocol for this test is to determine
testosterone levels in a blood sample drawn before and 60 minutes after
injection of GnRH at doses of 2 mg/kg or 50 mg/dog, IM [21]. An increase
in testosterone concentrations in the post-treatment blood sample would,
in such cases, be diagnostic for a cryptorchid dog.
In a cryptorchid cat, examination of the penis for presence of spines is
an excellent diagnostic technique. Penile spines, which are testosterone
dependent, become atrophied within 6 weeks after castration.

Case of feline cryptorchidism - adapted from Memon et al., [25].
A 4-year-old male domestic long hair cat was referred because of
aggressive behavior and urine spraying. He was obtained as a 3-month-old
kitten, and when he was 6 month old, only 1 testis was found in the
scrotum. When he was 1 year old, surgery was performed to remove the
scrotal right testis. The left testis was not found either within the
scrotum or within the abdomen. He developed male behavior and another
laparotomy was performed 1 year later; however, the left testis again
could not be located. He continued to show male behavior such as
spraying urine, loud vocalization, and aggressiveness.
At referral, digital palpation and ultrasonography did not reveal the
left testis in the scrotum or in the inguinal canal. The penis was well
developed and had penile spines (Fig. 3) instead of absence of penile
spines, which is characteristic of castrated cats (Fig. 4).
 
 
This was evidence of testosterone production. The cat was irritable and
difficult to handle. A blood sample was taken for baseline testosterone
concentrations, and 500 IU of hCG was administered IV. Blood samples
were taken again at 30 minutes and 2 hours after hCG administration.
Testosterone values (ng/ml) for samples taken at baseline, 30 minutes,
and 2 hours after hCG administration were 0.68, 5.0, and 10.5,
respectively.
With the cat under general anesthesia, a midline laparotomy was
performed. The left ductus deferens was identified and followed from the
prostate gland. The ductus deferens was found to course through the
inguinal ring caudally in to the subcutaneous tissues overlying the
pubis. The left testis was located in the facial plane lateral to the
pubic symphysis. Histological examination of the testis revealed
impaired spermatogenesis, seminiferous tubules lined almost entirely by
Sertoli cells, and diffuse interstitial (Leydig) cell hyperplasia.
Six weeks after the surgery, the hCG stimulation test was repeated.
Testosterone was not detected in any sample. Within a few weeks after
the surgery, improvement in cat's behavior (urine spraying, loud
vocalization, and aggressiveness) was reported by the
owner.

Case summary - hCG stimulation test proved to be a useful diagnostic
method for detection of the cryptorchid testis. On exploratory surgery
the cryptorchid testis was found by following the ductus deferens. In
this case, previous attempts to locate the retained testis had been
frustrated by the inability to palpate the testis subcutaneously and
locate the testis intra-abdominally. The most practical solution to
locate undescended testis would have been to follow the intact ductus
deferens to the small testis
adjacent to the pubic symphysis.

Megan