296 On Prophysaon, etc. 



prostate gland is large. The vas deferens is extremely long, ten times 

 as long as the penis, and equals the length of the whole genital system. 

 It is attached to the side of the vagina quite to the penis, where it 

 becomes free, and is spirally wound. It is largest about half-way from 

 the vagina to the apex of the penis. It enters the penis at the centre of 

 its truncated apex. The penis is very short and stout, barrel shaped, of 

 equal breadth throughout. It has no retractor muscle. The cloaca is 

 very short. On the vagina, just above the penis, appears on some speci- 

 mens an extremely small, sac-like organ, not figured in our plate, as we 

 are not entirely satisfied as to its presence. It is perhaps a dart sac, or a 

 prostate. The ovary has the usual tongue-shaped form. The oviduct is 

 not much convoluted. The vagina is long, and extremely broad, several 

 times convoluted. The genital bladder is oval, small, with a short, stout 

 duct entering the vagina at its upper extremity, by the side of the ter- 

 minus of the oviduct. 



This peculiarly stout, barrel shaped penis and broad vagina 

 were constant in eight specimens examined, all from Astoria. 

 In several other specimens from Mendocino County, easily 

 detected exteriorly by a more slender, tapering bod}^, and 

 smaller, more rounded mantle, the penis was found more 

 elongated, the vagina less broad, the genital bladder larger, 

 with a more delicate duct. In these specimens, also, the 

 testicle was very much larger and was not concealed in the 

 liver, but only slightly entangled in it at one point, against 

 which it lay. The epididymis in these specimens was also 

 free from the liver. The genitalia of this form differ enough 

 from those of the Astoria specimens to warrant our belief in 

 the existence of a second species of Pfophysaon. We have 

 therefore figured, also (fig. 5), the genital system of the 

 Mendocino County specimens. The question of specific 

 identity must be settled by those who can study living speci- 

 mens. The digestive system of the same form is figured on 

 pi. xiii, fig. 3. It quite resembles that of Arion hortensis as 

 figured by Leidy in Terrestrial MoUusks, Vol. I. It is 

 much more simple than that of Ariolimax. The salivary 

 glands are very broad and very arborescent, and form a 

 broad collar around the oesophagus and commencement of the 

 stomach. The last named organ is very broad. 



