3S PROF. M. M. HARTOG ON THE 



given by Jurine (whose book I only know at secondhand), Claus, and especially Vernet, 

 the following is the process : — The male seizes the female in the clasping-joint of his 

 antennules by her fourth pair of oar-feet, the ventral surfaces of the two animals towards 

 one another. The male then pulls itself up, so that its genital openings come to a level 

 with the copulatory pore of the female, and expels its spermatophores, which become 

 fastened to the pore, each presumably undergoing a torsion in expulsion, so that the 

 apex, which looked towards the middle line, now turns forwards and adheres to the 

 pore of the female. The globular elements of the spermatophores then swell up and 

 drive the spermatozoa out into the spermatheca. The two empty sacs of the sperma- 

 tophores remain attached for a short time to the female ; there they swell up and become 

 rounded. As is well-known, Cyclops is never parthenogenetic, but one fertilization 

 suffices for many broods of ova. 



The Position of the Copepoda in the Crustacean Phylum. 



In my work, lasting as it has done over a considerable time, it has been constantly in 

 my mind to trace out morphological relations ; and the conclusion to which I have been led, 

 that the Copepoda actually represent the ancestral form of the Crustacea, is one which 

 carries to me the greater weight in view of Balfour's opinion that they " are undoubtedly 

 among the lowest Crustacea which are free, or do not lead a parasitic existence," and 

 that " they may claim to be very primitive forms, which have diverged to no great extent 

 from the main line of Crustacean development," assigning as reasons their retention of : — 



(a) " The median frontal eye as the sole organ of vision," which I would put thus : — The plasticity of 

 the eye, derivable from the triune inverted eye of the Nauplius, and the absence of eyes of the paired 

 compound type found in other Phyla, which we may term the " Phyllopod eye." 



(b) " The simple biramous " swimming-legs, and indeed the character of the appendages generally, 

 and " other characters " of which I give a list. 



(b') The plasticity of the maxilla. (To be considered with b.) 



(c) The small development of the pleura, never enclosing the body, nor limiting infra-pleural epimcra. 



(d) The absence of gills, and the functional anal respiration. 



(e) The plasticity of the fore part of the alimentary canal. 

 (/) The circulation. 



(g) The general form of the body. 



Under each heading I propose to make a few remarks before sketching out what seems 

 to be a not impossible phylum of the Crustacea. 



(a). The eye of the Copepoda is, with few exceptions, derivable from the type of Cyclops or 

 Calanella. In Pontellidse the several ocelli are separated, their number often augmented, 

 and lenses sometimes superadded ; in Corycseidse the lateral eyes are widely separated 

 from the median, and peculiar in many ways, but contain " inverted " bacilli, the 

 nerve entering on their distal side, as first noticed by Claus and confirmed by Grenadier *. 

 Now this eye, which we may term the " Nauplius eye," is found, scarcely varying from 

 its typical condition (so far as one can judge from figures and specimens), in almost all 



* Op. cit. p. 66, t. vi. figs. 39-43. 



