NOTES ON SOME BRITISH NUDIBRANCHS. 341 



(1) D. plcDiata. This is a remarkably flat form, which appears not to 

 exceed an inch in length in British waters. The dorsal surface is 

 finely granulated, there is a distinct labial armature, and the radula 

 is decidedly of the type of Geitodoris, Bergh, that is to say, there are 

 two kinds of teeth, the inner teeth being of the ordinary hamate shape, 

 and the outer very thin and crowded together in sheaves. It is possible 

 that some specimens (about 50 mm. long) which I have received from the 

 Cape Verde Islands may be adults of this species. They resemble the 

 Plymouth specimens, except that they are much larger and were red in 

 life. The richer colour may perhaps be due to the climate. 



(2) D. testudinaria. Tiiis is a plump form of considerable size 

 (60 mm.). The back is covered with flat tubercles, which are sometimes 

 arranged in a stellate pattern. In the specimens from Plymouth, which 

 1 have myself examined, there is no labial armature, but Vayssiere 

 states that it is present in the Mediterranean form, which is otherwise 

 undistinguishable. The radula is not unlike that of the last species, 

 but the differentiation of the teeth is less marked. The outer are 

 thinner than the inner ones, but the change is less abrupt, and tlie 

 thinner teeth are not gathered together in such distinct sheaves or 

 packets. 



The names Platydoris testudinaria and Platydoris planata would seem 

 to be in any case incorrect, for none of the animals have the characters 

 of Platydoris (which include a peculiar hard consistency and an 

 armature of hooked scales on the reproductive organs). It is possible, 

 but not demonstrable, tliat the Doris testudinaria, of Ki.sso was a Platy- 

 doris; but, if so, it is neither tlie D. testiulinaria nor the D. planata of 

 Alder and Hancock. 



Alder and Hancock's type specimen labelled " Doris testudinaria, 

 Herm," has been kindly lent me by the Council of the Hancock Museum, 

 Newcastle. 



It is 30 mm. long, 23 broad, and 15 high. The mantle margin is 

 broken in many places, but it apparently covered the sides and the 

 foot entirely in its original condition. The general colour of the 

 animal is greyish yellow. Some of the dorsal tubercles are lighter than 

 the surrounding surface. There are some reddish spots on the under 

 side of the mantle. 



The texture is soft, and the specimen is a little decayed. Tiie back 

 is covered with low flat warts of various sizes. No stellate arrange- 

 ment is visible. The branchial and rhinophorial pockets are surrounded 

 by tubercles which do not amount to valves. The brauchiic are 

 retracted within the pocket, and their number could not be ascertained. 

 The anterior part of the animal is much retracted, but the long linear 

 tentacles are clearly visible. 



