238 JOURN'AT. OF GONCHOLOGV, VOL. II, NO. 8, OCTOBER, I905. 



BORNELLID^. 



Bornella digitata Adams & Reeve. 



Eliot, "Nudibranchs from E. Africa and Zanzibar, V.," Proc. 

 Zool. Soc, 1904, vol. 2, pp. 100-102, and references quoted there. 



Twenty-nine specimens from Karachi. The living animals are said 

 to have been of a very light flesh colour, with red markings and a red 

 ring or spot near the end of each branch of the cerata. 



They all appear to belong to the type of B. digitata, not B. arbor- 

 escens. The larger are about 30 mm. long., the smaller 15-20 mm. 

 All have at least five pairs of cerata, and the larger have six or seven 

 pairs. The first pair of cerata are nearly always trifid, occasionally 

 quadrifid, and rarely bifid. The second, third, and fourth pairs are 

 generally bifid, but some of them are occasionally trifid. The fifth, 

 sixth, and seventh pairs are simple. The first pair usually bear two 

 branchicc — less frequently three. The second, third, and fourth two 

 branchiae, the fifth one branchia, and the sixth and seventh none. 

 The rosettes over the mouth are well developed in all the specimens, 

 and generally contain about twelve tubercles each. The rhinophore 

 sheaths always bear three comparatively short processes in front, and 

 a single conspicuously long one behind. 



These specimens are somewhat more liberally furnished with 

 cerata than those which I have found on the East Coast of Africa, 

 and agree in this respect with those described by Bergh from the 

 Philippines, and by Alder and Hancock from the East Coast of India. 



PLEUROPHYLLIDIADyE. 



It is somewhat remarkable that so small a collection should con- 

 tain three species of this family, which is by no means abundant, 

 though widely spread in the Indo-Pacific. The Pleurophyllidiadse 

 are rare in the littoral zone, and appear to frequent moderate depths, 

 where they are generally found in sand or mud. Two specimens 

 belong to Plcurophyllidia and one to Linguella^ which differs from the 

 former genus in that the anterior margin of the mantle does not form 

 an unbroken fold behind the rhinophores, but passes between them, 

 and is continuous with the surface in front of tiiem. 



The species of Pleurophyllidia are characterized with a distinctness 

 unusual in Nudibranchs. Besides the dentition, which is different for 

 each known species, good characters are offered by the markings on 

 the back which are generally longitudinal stripes, but sometimes 

 tubercles, by tlie lamelh'e in the underside of the mantle, and the 

 papillae or othei' prominences on the tentacular shield. 



Pleurophyllidia semperi Bergh. (PI. V., fig. 7). 



Bergh, "IJidrag Monogr. Pleurophyllidierne," p. 37 ; /c/., " Alal. 

 uch," Senipa's Reisen, vi., p. 249. 



