ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 731 



In young specimens of Serolis schythei the future hyaline cells are 

 small and granular, and inclose the extremity of this axial cone and 

 fibres, which may be partly a product of their activity, though chiefly 

 formed by the other retinula cells. Each retinula, therefore, consists of 

 two central clear cells (corresponding in number to the cells of each 

 vitrella), surrounded by four or seven pigmented cells. 



The pigmented retinula cells are connected with transversely striate 

 fibres, which pass into the ganglion, and are generally regarded as 

 nerve-fibres. The hyaline cells do not end in a nervous filament, 

 unless the axial cuticular rod, which is hollow, incloses a nerve-fibre. 

 The specialization of the retinula into clear and pigmented cells recalls 

 the eye of certain Annelids and Molluscs. The eye is ' diplostichous,' 

 the upper row of cells forming the vitrella, and the lower row the 

 retinula. To this extent, therefore, Mr. Beddard's results harmonize 

 rather with those of Grenacher than with those of Patten. 



New Species of Ceponinse.* — MM. A. Giard and J. Bonnier have, 

 since tbe publication of their monograph on Cepon elegans, received a 

 number of new forms allied to that parasite. On Nautilograpsus there 

 is a species which it is proposed to call Gi-apsicepon Edwardsi ; it is 

 apparently rather common. Although it does not produce any apparent 

 deformation of the carapace, its presence can be easily enough detected 

 on account of the transparency of its host's integument. The male is 

 much less degraded than that of other Ceponinse, and therein it approaches 

 Leidya. The species found on Trapezia dentifrons is called G. amicorum, 

 but unfortunately, only one example is as yet known ; on the whole, 

 however, its characters, so far as it has been possible to make them out, 

 are rather those of members of the group which are parasitic on Grapsidse 

 than of the parasites of Gelasimidse ; and, as is known, it is with the 

 former that Milne-Edwards, in opposition to Nauck, is inclined to place 

 the genus Trapezia. 



The name of Portunicepon Hendersoni is given to a parasite of 

 TJialamita callianassa, which appears to be pretty common at Madras. 

 This parasite produces a very slight deformation of the carapace ; the 

 male is very degraded, pigment being rare, and the lateral lobes of the 

 pygidium almost fused with the median part. 



Grapsicepon Edimrdsi is the first example of a Bopyrid being found 

 parasitic on other Crustacea than those of small bays with quiet waters, 

 for it was brought from the Sargasso Sea. Prof. A. Milne-Edwards has 

 lately found a magnificent Bopyrid, which it is proposed to call 

 Pleurocrypta formosa, on PtycJiogaster formosus, a splendid Galatheid, 

 which was dredged by the ' Talisman ' at a depth of 946 metres. 



Geographical Distribution of Diaptomus.f — MM. J. de Guerne 

 and J. Richard bring forward evidence in favour of the cosmopolitan 

 range of this fresh-water Copepod ; further investigations will probably 

 show that many of the species already described have a wider range 

 than is yet assigned to them. 



So-called Mucous Gland of Male Cypridse.if: — Herr C. G. Schwarz 

 has investigated the structure of the so-called mucous gland of the male 

 Cypridse. It is, as he observes, a remarkable thing that we should be 



* Comptes Eendus, cvii. (1888) pp. 44-7. f Ibid., pp. 47-50. 



X Ber. Naturf, Gesell. Freiburg i. B., ill. (1888) pp. 133-58 (2 pis.). 



