The Opisthobfanchia/a of South Africa. 67 



diameter of 0'075 mm. ; the otocysts of a diameter of 0-08 mm., 

 filled with otokonia of a diameter up to 0'009 mm. The skin of the 

 back, the appendages of the back and the stalk of the rhinophores 

 (but not the lamellae) full of very long, very hardened spicules of a 

 diameter up to 0-035 mm. The interstitial connective tissue filled 

 with spicules. 



The bidbus 'pharyngeus scarcely 1 mm. in length ; the hardened 

 state of the organ did not permit a thorough examination. The lip 

 disc only clothed with a thin cuticle. The number of rows of tooth- 

 plates altogether perhaps about 55, on the outside of the lateral 

 plates about 15 outer. The plates were nearly colourless ; the 

 length of the second lateral plate was 0'06 mm., that of the first of 

 the outer plates 0-037, of the outermost 0-029 mm. The first and 

 second lateral plates (fig. lab) as formerly described ''•' in Tr. clavigera, 

 so too the outer plates (fig. 7c). 



The posterior visceral mass grayish brown, the anterior genital 

 mass whitish. The armature of the glans was not seen. 



The form here examined is no doubt the Tr. lucida of Stimpson, 

 which hitherto was only known from his imperfect description. 



NEMBEOTHA, Bgh. 



E. Bergh, System der nudibranchiaten Gasteropoden, I.e., 1892, 

 pp. 1144-1145. — Die Opisthobranchiata d. Siboga Exped., 

 1905, pp. 194-202. 



Corpus limaciforme, fere Iseve ; rhinophoria retractilia clavo per- 

 foliato ; branchia in medio fere dorsi sita, paucifoliata, foliolis hi- vel 

 tripinnatis ; tentacula brevia lobiformia ; podarium angustius. 



Arniatura labialis debilis vel nulla. Eadula non lata ; rhachis 

 dente subquadrato applanato ; pleurae dente laterali (primo) falci- 

 fornii et dentibus externis compluribus depressis simplicibus. 



Glandula hermaphrodisiaca hepate connata ; prostata nulla ; glans 

 penis aculeis vel hamis armata. 



Outwardly the Nembrothae are not always easily to be distin- 

 guished from the Trevelyanae ; the nuviber of their branchial leaves is 

 svuiller than in this genus, but the anatomy shows very important 

 differences. The nature of the ra-sj; is very different ; and the her- 

 maphrodite gland clothes (as common in other allied forms) the liver ; 

 there exists no special prostata, and the (glans) penis is armed. 



* R. Bergh, Beitr. zu einer Monogr. d. Polyceraden, ii. Verb. d. k.k. zool. 

 hot. Ges. ill Wien, xxx., 1881, p. 643. taf. xiii., fig. 9a6 ; taf. xiv. , figs. 2 3. 



