OPISTHOBRANCHIATE MOLLUSCA FROM MONTEREY BAY. 139 



The cfi-ophagus is relatively short, being but 3 mm. in length, is curveii to the left, and jtasses intn 

 the large thin-walled saccular stomach, the greater jiortion of which lie.s in fnmt of the liver and 

 entirely free from that organ, its' pyloric portion only being inclosed in a deep oblique furrow which 

 divides that organ into a smaller anterior and a larger posterior lobe. The intestine courses to the left 

 in this groove, doubles downward and forward, thence describing a loop upward to the dorsal surface 

 of the viscera, where it passes in a wide curve over the surface of the anterior genital mass posteriorly 

 to the anus. 



The hermaphroditic gland covers the anterior upper face of the liver, its duct arising from the upper 

 surface close to the pyloric end of the stomach by the union of two main branches, which are lost in 

 fine ramifications in the substance of the gland. The duct is short, dilating into the long convoluted 

 whitish ampulla which courses forward, pas.sing beneath the anterior genital mass in a series of 

 loopings in a groove between the nidamental gland on the right and the large spermatotheca on the 

 left. The total length of the hermaphroditic ampulla is about 12 mm., nearly one-half the total length 

 of the whole animal. At the anterior face it passes into the nidamental gland, giving off the spermatic 

 duct, which emerges from the substance of the gland and at once dilates into the thick lobulated 

 prijstate gland. This organ is broad and describes an S-shaped loop upon the anterior and inner faces 

 of the anterior genital mass, forming with the spermatotheca, which it closely covers, fully one-half the 

 bulk of the mass. Its distal end passes into the narrow muscular vas deferens, which, after a very 

 short and somewhat tortuous course, dilates into its spindle-shaped ampulla, 2 mm. long and 1 nun. in 

 diameter, lying obliquely upon the dorsal face of the anterior genital mass and inclosed in the loop of 

 the intestine. The wall of this ampulla is very much thickened and muscular. Beyond it the vas 

 deferens doubles outward upon itself and courses obliquely forward and outward, dilating into the 

 prcputium, a cylindro-conical structure 2.5 mm. long and 1.5 mm. in greatest diameter. At its base 

 projects the blunt glans penis, armed with minute hooks. 



The vagina is short and cylindrical, passing straight inward for 2.2 mm., when it makes a sharp 

 tarn posteriorly and, tapering for 1.5 mm., passes into the much narrower vaginal duct, which, with 

 a length of 1 mm., opens into the spermatotheca upon its upper face. The spermatotheca is a large 

 spherical organ, 2 mm. in diameter, its anterior lower and inner faces nearly covered by the loops 

 of the large prostate gland, which also overlaps a portion of its upper surface. The exit of the uterine 

 duct from the spermatotheca is 1 mm. distant from the entrance of the vaginal duct and is situated 

 uiiun its anterior face. The uterine duct is slender and passes downward and outward, being com- 

 pletely concealed by the overlying lobules of the prostate. It is about 2.5 mm. in length, and just 

 before entering the nidamental gland receives the duct of the spermatocyst, a small pear-shaped sac 

 lying upon the upjier anterior face of the anterior genital mass, its surface e.xposed between the distal 

 portion of the vas deferens and the top of the prostate gland. 



The nidamental-albumen gland complex is small, about 2.5 mm. in length, 2 mm. in height, and 

 1 nun. in thickness. Its outer surface is conve.x, the inner irregularly faceted. The gland is about 

 eiiually divided between the albuminous and nidamental portions, the former occupying the upper and 

 the latter tlic Inwer portions, respectively. The relations of the ducts are as usual. 



The largest sjiecimen taken had a total length of 52 mm., breadth 10 mm., ami height 11 mm., 

 though the majority of individuals are much smaller than this, averaging perhaps 30 to 40 mm. in 

 length. 



Habitat; Aliundant everywhere during the summer months in rocky tide pools all along the coast 

 from Monterey to Point Lobos. During the winter months it is not so abundant, but is never entirely 

 lacking. 



Type no. 181276, U. S. National Museum. 



15. Triopha grandis :MacFarland. 



Triopha ijramlis MacFarland, op. cit., p. 50. 



Body large, the largest specimen measuring 80 mm. in length, 25 mm. in width, and 30 mm. in 

 height in alcoholic material. Plump, not at all depressed nor compressed, highest in region of the 

 heart and sloping rapidly backward to tip of the short, blunt tail, more gently sloping forward. 



