Miscellaneous, 303 



I have not been able to trace from its commencement the appear- 

 ance of the spermatozoids ; I have, however, once seen them united 

 by the head, in great numbers, in their mother cells (male ovules) ; 

 the latter then burst, and the spermatozoids group themselves in a 

 single bundle in a large sac with thin walls without epithelium. 

 Between this sac and the testicular pouch float a number of corpus- 

 cles measuring 0"0045 millim., the nature of which is unknown to me. 



I cannot regard the dorsal cord as formed of cells (Quatrefages) 

 or of disks (J. Miiller &c.). Longitudinal sections showed a more 

 regular structure, namely lamellae composed of semisolid amorphous 

 material. But these lamellae towards the centre of the dorsal cord 

 are forked in proportion as they recede from that centre, giving ori- 

 gin to secondary lamellae in gradually increasing numbers, which do 

 not reach the whole surface of the dorsal cord. Hence arise those 

 parallel lines which have led to the belief in juxtaposed disks, and 

 which, occupying a part of the circumference, have been regarded 

 by M. de Quatrefages as limiting large flattened cells. Nor can I 

 share the opinion of M. Marcusen, according to which the large 

 bodies contained in the cells of the fin on the one hand, and in the 

 swelled extremity of the spinal marrow on the other, are composed 

 of capillaries. In the first place, the large bodies are translucid 

 and homogeneous, whilst the swollen extremity (so well described by 

 M. de Quatrefages) is filled with corpuscles perfectly similar to those 

 which strike us at the first glance in the spinal marrow. Secondly, 

 in some fragments of Amphioxus which had been cut for several 

 days, and were still living, these parts preserved their dimensions, 

 which would not have been the case if they had been composed of 

 capillaries full of blood. The spinal marrow contains, both in the 

 swollen and contracted parts, some cells which are very difficult to 

 see clearly. They did not appear to me to be round, as is generally 

 stated, but angular or polar. I have seen from an angle on one of 

 them, which was tripolar and measured O'OIS millim., a fibre origi- 

 nate and soon become bifurcated. 



The manifest contradiction between the description of M. de 

 Quatrefages and that of M. Marcusen with regard to the termination 

 of the cutaneous nerves appears to me to be founded on a premature 

 generalization. If we examine the cutaneous nerves in the middle 

 and posterior regions of the body, we find them ramifying more 

 and more, losing their proper envelope, and at last becoming so fine 

 that their extremities cannot be distinguished. I have reason to 

 believe that they present anastomoses in their course. But the 

 nerves which proceed from the facial trunks (second, third, fourth, 

 and fifth pairs of Quatrefages) behave diff'erently ; after a short 

 course, they arrive at some oval cellular bodies, measuring from 

 0-012 to 0*015 millim., filled with granules, with one or two nuclei 

 of 0*004 millim. These cells, pointed out by Quatrefages, are the 

 very terminations of the nervous filaments ; but they only exist for 

 the facial filaments, in which they undoubtedly indicate some parti- 

 cular function. 



The anterior termination of the spinal marrow of Amphioxus, 

 although not inflated, nevertheless plays the part of an encephalon ; 



