﻿PYCNOGONIDA. jj 



in both sexes as combs or cleansing apparatns for the other limbs of the animal, all of which can 

 presumably be brought within the sphere of action of the rows of dermal leaves") (the comb) with 

 which the last joints of the o\-igerons legs are provided. 



The terminal part of the ovigerous leg [Pars trr»ii)ialis pedis orijcri), fig. i pfr. 



Sars: Endeled (pars terminalis). 



I have, as Sars, given a special name to these four last joints of the ovigerous leg, bearing 

 the comb or cleansing apparatus, just mentioned. The comb consists of a greater or lesser number 

 of daggershaped dermal lea\-es with deeph" incised edges, arising in one or more row's from the inner 

 side of these foiu* joints. The claw, with which the leg terminates, is closely joined to the comb, and 

 as it is often deeph' incised in its inner edge it also partakes in the work of the comb. 



The egg- globe (globus ovoruin)^ fig. i glov. 



Sars: ^5Jggeklump (globa ovorum). 



The male, as it is well known, (Cavanna, Studi Picnog., 1877) carries the deposited eggs, 

 placed in lumps around one or more of the middle joints of the ovigerous legs. As the size of the 

 eggs is verv different in the different Pycnogonida, so it is also with that of the lumps, but most 

 frequenth' the size of the lumps and of the eggs stands in an iu\-erse ratio to each other. As a rare 

 exception the males of some species carry the eggs in one cake on the lower side of the body [Pyc- 

 }iogonuin), while the males of other species have some few, very large eggs attached singly to the 

 ovigerous legs {Pallciic). The number of egg-globes most frequenth- is two, one globe on each of the 

 two legs, but frequently this nmuber is doubled or increases further to 4 — 5 globes on each leg. \'ery 

 rarely only one leg has one single egg-globe; I have, however, found this to be the case in by far 

 the most of the males of Nyiiiplioi robiistuiii , that I have had for examination. 



The preceding sur\-e\- of the limbs and parts of the body of the Pycnogonida applies also to 

 the \oung larvae, in so far as those limbs and parts have been developed; but besides these larv£e 

 have particular limbs, and to show these limbs I have on p. 3 given a contour-drawing of such a 

 larva, fig. 2. Especialh- are to be mentioned : 



Embryonal leg of the first pair (Pes eiiibrvoi/nlis prion's pan's), fig. 2 b. 



Embrvonal leg of the second pair (Pes e/i/liryoi/alis alferiiis pans], fig. 2 c. 



These two pairs of limbs develop at the same time as the chelifori (or the first pair of embry- 

 onal legs) and the proboscis on the first chief part of the embryo; they soon attain to their full devel- 

 opment, but are also early thrown off during the second or third larval stage. Onl\- rarely they are 

 not developed at all (Pa/lei/e Iiastafa, pi. I, fig. 18— 19) or grow only to .short, tap-like processes {Pscu- 

 dopalleiie spiiiipcs, pi. I, fig. 8, and Pseud, eireularis, fig. 10, as well as Palkne brevirosiris, fig. 16). 



The History of Development. 



On the development of the Pycnogonida there exists a rather considerable literature. The 

 attention must first be drawn to the fact that the common distinction, also u.sed in this work, which 



■) By Sars these leaves or l>laik-s are rather iinhickily iiaiiieil RaiicUonier , ill ICiiJilish . marginal spines-. 



2* 



