

i iO( i\m.\ 



in the second stage, but not of the same degree of development In 



. pi. II, Kg. ii, tin.- three foremost pairs of ambulator] legs arc all developed, 



ommonl) is the case, .ill developed to the same degree. The byssus-gland is 



developed than usual. In the somewhat older larva, fij, r . [2, the first pair of ambulatory 



isual, much inure developed than the second pair, and the third pair is not even 



1 m ■ Sluiteri I have also drawn a phase of the second stage, pi. II, t i 14. . 17, viewed from 



the side, and Kg. is. viewed from below, but they show nothing remarkable with regard to the develop- 

 ment of the limbs. 



Of Pycnogonum littorale I have an interesting drawing, pi. I, Kg.4. The specimen was taken 

 igo by the present doctores, Mr. Hector Jungersen and Mr. Johannes 

 Petersen, at Frederikshavn without particular statements as to the circumstances in which it was 

 found. It can l>e no other than a larva in the close of the second stage of a Pycnogonum s. str. , but 

 from Frederikshavn and upon the whole from Denmark we know of no other Pycnogonum than /'. 

 rale, which moreover is commonly found on the locality in question. The embryonal limbs have 

 idj quite disappeared, and no traces are to be seen, either from the upper side, represented lure, 

 or from the lower side. That these limbs have disappeared is no wonder, as they usually do so, if 

 not so quickly, at all events in a short time; more remarkable is the absence of the chelifori. In 

 other instances the chelifori are embryonal limbs which are kept throughout the life of the animal, if 

 not always with a fully developed chela, at all events, though, with fragments of it, and only in a 

 few forms, the genera Pycnogonum and Phoxichilus, the so-called order Acerata of Sars, and in 

 his family Colossendeida, the chelifori are quite wanting in the full-grown animal; there is, however, 

 reat possibility that the chelifori of the last-mentioned family are not thrown off until an advanced 

 e, after the close of the larval development Such, at all events, i> the case in Colossendeis 

 ista (and gracilis) according to the observations of Hock, which observations I shall here aug- 

 ment very much (in another Coloss. (macerrima) I have found the chelifori thrown off already in a 

 very young animal). The larva of Pycnogonum drawn here, is, judging by the development <<i the 

 ambulati 1 legs, in the close of the second stage, all three pairs of legs having reached the full seg- 

 mentation, also the claw. The body and the legs are smooth and naked, without the thick, nigged 

 skeleton distinguishing the grown Pycnogonum, and only the oculiferous tubercle and the three 

 knobs in the middle line of the back remind of the rugged appearance of the animal. The Krst seg- 

 ment of the trunk is uncommonly and unproportionally large. 



The genera Pallene and Pseudopallene are distinguished from the other Pycnogonida, not only 

 by tl e mentioned absence, or rudimentary state of the embryonal legs, but also by the two 



1 ambulator) legs arising contemporaneously, growing, and attaining to a considerable 

 pment, before the growth of the third pair of legs begins. Of Pallene I have examined two 

 Pall. f>r and Pall, hastata. The former, Pall, brevirostris \ is given on a rather early 



. in which the two pairs of ambulatory legs are somewhat short and thick, with a single con- 

 in the middle besides the claw, pi. I, Kg. 16; a special distinction is the separation, ahead) 

 menl ling, of the byssus-gland in particular dermal glands, each with a byssus-thread 



