COMPARATIVE MOEPHOLOGY OF THE GALEODID.E. 385 



preserved for tvustworthy observations on the egg and yolk formation. With regard to 

 the latter, I have seen most of tlie interesting phenomena described by Birula. In 

 addition to the follicular membrane surrounding the eggs, the latter develop tough, 

 membranes of their own with a definite structure {cf. PI. XXXIV. fig. 16, em), the 

 outermost j^ortion being finely laminate, the innermost radially striated as if liighly 

 jjorous. 



I have found no ripe eggs within the ovary. On the other hand, the " ovaries " are 

 often found distended with the large oval glittering spermatophorcs which, when first 

 seen, I took to be eggs. Birula seems to be the only writer who recognized them to be 

 spermatophorcs ; both Dufour and Kittary describe them as eggs. Such an error is 

 well calculated to throw our knowledge of this svibject into confusion. Indeed, 

 we are still not clear on many points. Ai-e the animals with their glands distended 

 with spermatophorcs {cf. PI. XXX. fig. 11) males or females ? Mr. Pocock has shown 

 me several whicli, from other characters, he thought were males, with their glands 

 similarly distended from end to end -with spermatophorcs. So far as our knowledge 

 goes, the males have no such capacious sacs, although they may be specially developed 

 at the breeding-season. All that we can really say is that certain specimens are found 

 with glands distended with spermatophorcs. As far as I can gather from Birula's 

 account, such specimens might be either males or females, since the glands in both 

 may be so distended. The question of sex seems to depend entirely upon our finding eggs 

 in process of development, or testes. The specimens having the spermatophores, 

 according to my experience, had no eggs ; but, on the other hand, the only specimen 

 showing testes had no such large receptacles to be distended in the manner described 

 (PI. XXX. fig. 11), although, as above stated, such sacs may perhaps develop as soon as 

 needed. To judge from Birula's description of the genital glands in the male of G. ater, 

 my figure, which represents a specimen of G. arahs, would be that of a male. The curious 

 posterior distension of the poi-tion where the gland curves round to run forward may be 

 secondary, and due to the enormous quantity of spermatophores produced. 



An undoubted ovary, with developing, eggs, I found filled from end to end wdth small 

 cells ; even the atrium was similarly crowded. These, according to Birula, are amoeboid 

 and devour the spermatophoral envelopes, the superfluous sperm-cells and unfertilized ova. 

 Considering that one spermatophorc apparently contains enough sperm to fertilize all the 

 po-o-s which could bud on the limited surface of the ovary, the waste must be enormous 

 when the latter is distended with sj)ermatophores, which seems sometimes to be the case. 

 The eo'gs are said to develop into embryos within the ovary, and the embryos are said to 

 be deposited, apparently in a very immatui-e condition, in holes in the ground. 



Male Organs. — I have been still less fortunate in making out the male organs, and, 

 further, what 1 have seen does not appear to agree with Birula's description. Perhaps 

 the difi'erences are specific. Dufour found two types of male glands. T have suc- 

 ceeded in finding the filiform testes twisting about among the alimentary diverticula 

 in only one specimen {G. arahs). The tubes Avere surrounded by a membrane hooped with 

 fibres, as are the alimentary diverticula. These fibres are probably muscular. 



SECOND SERIES. — ZOOLOGY, VOL. VI. 51 



