242 JOURXAI. OF CONCHOI.OGY, VOL. II, NO. 8, OCTOBER, I905. 



Both Ihe preserved specimens are of a dirty opaque-white, with 

 orange-yellow pigment on the appendages, rhinophore-sheaths and 

 branchiae. The larger specimen has a few orange-yellow spots on the 

 anterior part of the body, and a few large greenish-black spots here 

 and there. In the smaller specimens the colours are similar, but both 

 the black and yellow spots are much more numerous and more 

 generally distributed, though smaller. 



The anterior part of the body seems to be much as in Alder and 

 Hancock's plate of Thecace.ru pennigera. No oral tentacles or oral 

 veil are visible, and the anterior margin of the foot is so much con- 

 tracted that its characters cannot be safely formulated. The foot, as 

 preserved, is rather narrow and terminates in a distinct tail. The 

 dorsal surface is smooth, and there is no trace of a mantle edge. The 

 rhinophores are perfoliate, and surrounded on three sides by large 

 and solid sheaths, which are open on the inside. The outline appears 

 to have been as in Alder and Hancock's plate, but it is difficult to 

 be certain. The branchiae also appear to be as represented by x\lder 

 and Hancock, and may be counted as either three or five, the 

 lateral plumes being deeply cleft. The plumes are stout and mostly 

 bi-pinnate. Behind the branchire are two stout cylindrical append- 

 ages, quite simple and showing no trace of division. The integuments 

 contain many spicules, which are fairly straight and bear numerous 

 little knobs or short branches. 



The central nervous system is yellowish, and markedly granulate. 

 The cerebro-pleural ganglia are roundish, not distinctly divided into 

 two halves ; the pedal ganglia are pear-shaped. The jaws are 

 yellowish-brown and bear a wing-shaped process as in Polycera. The 

 cutting edge is irregular, but not denticulate. The radula consists of 

 nine rows in both specimens, the formula being 9 x 3 -f 2. o. 2 -I- 3. 

 The rhachis is bare, the two innermost teeth yellowish-brown, the 

 three outer colourless. The first lateral is hamate, rather small, and 

 has a projection on the side just above the base which is fairly long. 

 The second lateral is considerably larger than the first, but with a 

 narrower base. The lower part of the side projects considerably as 

 a prominent ledge. The third tooth is much flatter, but bears a low 

 cusp, and the base is prolonged into a short tail ; this tail is visible 

 also in the fourth tooth, which is a mere plate without any cusp. The 

 fifth tooth is a small curved plate. The liver is greyish and not 

 divided ; it is covered by the whitish hermaphrodite gland. The 

 penis is long, and bears a thick armature of minute hamate spines. 



This species approaches so closely to T. pennigera that one may 

 doubt if it is not identical with it. The difference in habitat and 

 climate ( Z! pennigera being recorded only from the British coast) 

 makes identity improbable, but the only certain points of difference 



