38 SUMMARY OF CURRENT RESEARCHES RELATING TO 



land snails. He now finds that it is most nearly allied to the West 

 African Atopocoddis, which is apparently also viviparous and has the 

 albumen-gland greatly reduced. 



Pigments of Nudibranchs.* — T. D. A. Cockerell calls attention to 

 the pigmentation in three hitherto undescribed species of Chromodoris, 

 e. g. — C. universitatis (bearing the colours of the University of California), 

 ultramarine aud cobalt-blue with orange spots. In this species and in 

 C. porter se, the blue dissolves out in formalin ; in C. mcfarlandi the 

 dominant pigment is purple and does not dissolve out. The blue solution 

 referred to is bleached by caustic potash, and turned pink by hydrochloric 

 acid. The orange is not affected by the formalin. No doubt all the pig- 

 ments illustrate " warning coloration." 



Relationship between Amphineura and Cephalopoda.^ — J.Graham 

 Kerr is of opinion that Prof. Ludwig Plate has failed to fully appreciate 

 his view as to the phylogenetic relation between these two groups of 

 Mollusca. Prof. Plate denies that Cephalopods can be regarded as 

 having descended from forms resembling Chitons ; but Mr. Kerr states 

 that he had no intention of maintaining such a position. He only 

 suggested that the Amphineura were the nearest living allies of the 

 Cephalopoda, that is, " that the ancestral group common to the two groups 

 was probably more recent than that common to either of them and any 

 other group of molluscs." This position the author considers is fully 

 justified by the existence in the two groups of numerous points of re- 

 semblance in regard to deep-seated morphological features without any 

 apparent adaptive relations to conditions of existence. 



Affinities of Phyllaplysia.J — Prof. G. Mazzarelli has been able to 

 make some observations on two species of this Molluscan genus, P. 

 lafonti and P. paulini sp. n. He figures and describes the brain, jaw, 

 penis, and radula teeth of the first species, and concludes that the genus 

 is most nearly allied to Notarchus, the two differing chiefly as regards 

 secondary characters. 



The Genus Chsetoderma.§ — A. Kowalevsky has obtained, while 

 dredging in the Sea of Marmara, two species of Chsetoderma, both of 

 which appear to be new. The first of these is characterised by the 

 presence of a complex radula, bearing nine rows of teeth ; it has in con- 

 sequence received the name of Ch. radulifcra, in order to mark the 

 contrast with other known species in which the radula is rudimentary. 

 The other species externally resembles to some extent both Ch. productum 

 and Ch. nitidulum, but differs from both in the structure of its radular 

 apparatus. The author makes it a lcw species, and names it Ch. gut- 

 turosum, from a curious habit which it displays of inflating the head- 

 region, a habit which is of great aid in burrowing. 



8. Lamellibranchiata. 



Formation of Pearls. || — Prof. E. Dubois finds that in Mytilus edulis 

 pearls are formed around a small Trematode — Distom'um luteum (?), or 



* Nature. Ixv. (1901) pp. 79-80. 



t Zoul. Anzeig., xxiv. (1901) pp. 437-S. J Tom. cit., pp. 433-7 (G figs.). 



§ Arch. Zool. Expe'r., ix. (1901) pp. 261-83 (3 pis.). 



|| Comptes Rendus, exxxiii. (1901) pp. G03-5. 



