532 PROF. C. H. DONOGHUE : REPORT ON 
tendency to fuse and form a sort of veil as in T. punctata. Below and in 
front of the right oral tentacle lies the penis. 
Foot. The foot is large and muscular and fairly broad. It is sharply 
maj'ked off from the head at the anterior end by a groove, and posteriorly it 
is continued .as a sort of tail. The pleuropodia arise as dorsally-directed 
flaps from the median and postero-lateral region of the foot. 
JRliinophores. The rhinophores are two sub-conical projections about 12 mm. 
high, situated near the mid-dorsal line about halfway between the oral 
tentacles and the front end of the pleuropodia. They are deeply grooved 
along the terminal portion of their postero-lateral borders. 
Gill or Ctenidium. The gill is well developed and is a lobate plume of 
orescentic shape. It is attached by a wide base along the antero-median 
margin of the pallial cavity, and posteriorly it passes out freely and the tip 
is exposed to a relatively greater extent than in the preceding species. 
Shell. The shell is pale yellow, transfiarent, with concentric lines of growth 
clearly showing, and it measures 28 mm. by 25 mm. (Smith's specimen 
measured 30 by 27 mm. — a fairly close approximation). The postero-dorsal 
umbo lies far back on the visceral mass. On the longer, more arched, left 
side of the shell lie a ridge and a groove which run parallel with the edge. 
Labial Armature. The inner parts of the buccal cavity are lined by a thin 
hyaline layer of cartilaginous consistency. This takes the form of a tube 
flattened laterally ; its internal dimensions are 5'7.5 mm. high by 1"5 mm. at 
its widest point and it is about 4 mm. long. It is strengthened by two 
slightly raised bands 2"5 mm. wide ; these almost touch dorsally, but are a 
little more separated ventrally. As in the preceding species they are com- 
posed of an enormous number of tightly packed circular rods. 
Radula. The radula is well developed and measured 12'5 mm. long by 
10*5 mm. wide when spread out on a slide. It is of a deep horn-yellow 
colour. The number of rows in the radula is about 48 and the number of 
teeth in the first row 3 {i. e., 1. 1. 1) ; in the tenth row 45 {i. e., 22. 1. 22) ; and 
in the thirty-fifth row about 87 {i.e., 43.1.43). The base of the rachidial 
tooth is roughly trapezoidal, with a deep rounded notch in the middle of the 
anterior border. The blade is leaf-shaped and relatively larger than in 
2\ ijigantea. It has a median spine bearing 3-4 lateral denticles and two 
lateral spines. The first of these has two lateral denticles and the other is 
smooth. The base of the first pleural tooth is approximately rhomboidal 
with curved sides ; its blade consists of two well-marked spines, the larger 
on the inside, and each bears a series of from 2-4 flanking denticles. The 
pleural teeth get larger as they pass Outwards, reaching their maximum well 
over halfway out. The blade becomes elongated and the spines much 
longer, but they retain their lateral denticles, about 3-5 in number. 
Finally, near the lateral margin, first the smaller spine disappears and then 
