COLLINGE : ON ANATOMY OF AMPHIDROMUS. 5 I 



f. p.); beyond the epiphallus there is a long flagellum, the extreme 

 distal portion of which is folded upon itself, and forms a globose sac, 

 with a short fleshy appendix (PI. iv, fig. 4, ap.). Internally the wall 

 of the penis is seen to consist of a series of muscular folds, which form 

 a fringe distally around the fleshy papilla. Around the base of the 

 papilla is a deep groove, from which arise a series of very fine grooves 

 coming up on all sides towards the somewhat crescent-shaped opening 

 (PI. iv, fig. 4). The retractor muscle of the penis is short, and 

 inserted on the right side towards its middle. The receptacular duct 

 enters the vagina to the left of the free-oviduct. It is a long, wide 

 tube, gradually tapering and terminating in the ovoid receptaculum 

 seminis. In life the duct is richly pigmented and coiled around the 

 common duct, so that the receptaculum seminis lies at the side of 

 the albumen gland. Internally the lower portion shows a rich folding 

 of the wall, which gives place to a series of longitudinal folds distally. 

 The free-oviduct is very short. The common duct is closely 

 wound upon itself for the greater part of its length. The albumen 

 gland is small. The hermaphrodite gland is somewhat fan-shaped, 

 with a fairly large, twisted duct. 



The Free Muscles. (PI. iv, figs, i, 2, 6). — The buccal retractor 

 consists of three more or less fused bands, inserted on the ventral 

 side of the buccal cavity (PL iv, figs, i, 2, 6). It is not united to the 

 ocular retractors, which are free. The right ocular anteriorly consists 

 of the superior and inferior oculars, and then fuses with the pedal 

 muscles, and is continued posteriorly as two bands. The left ocular 

 anteriorly is similar to the right one, posteriorly it is continued as a 

 single band. Lying between the two oculars and dorsal to them (in 

 dissection) is the large columella muscle. The retractor of the penis 

 has already been mentioned, it arises from the diaphragm. 



The Fallial Region. PI. iv, fig. 7). — The kidney is a long, narrow, 

 ribbon-like body measuring 47 millim. in length, and varying from 

 4'5 millini. to 5 '5 millim. in breadth. The pericardium is g millim. 

 in length. 



Compared with the species which have so far been anatomically 

 described, the following features seem to characterize A. palaceus. 



I. — In the general form of the generative organs there are minor 

 features, and more important ones in the form and structure of the 

 penis and epiphallus. 



2. — -The form and position of the free muscles. 



3. — The general characters of the kidney, ureter, etc. 



