REPOflT ON THE PYCNOGONIDA. 107 



wall, £i*om the one longitudinal ridge to the other ; whereas in Ascorhynchus glaber 

 (fig. 9) the row of pores is placed almost exactly opposite to the single but very strong 

 ridge. 



In Pallene and Phoxichilidium the structure and the position of the glands show 

 nothing particularly interesting. In Pallene there are many pores, in Phoxichilidium 

 insigne only a single pore at the end of the joint, placed at the tip of a conical 

 excrescence (PI. XVI. fig. 18A;). The structure of these glands in Colossendeis 

 is extremely interesting. In the three species of this genus in which I studied them, 

 Colossendeis leptorhynchus, Hoek, Colossendeis megcdonyx, Hoek, and Colossendeis pro- 

 hoscidea, Sab. (sp.), the gland consists of very numerous more or less isolated parts of 

 a rounded or more longitudinal shape, each of them opening separately by a distinct pore, 

 or {Colossendeis prohoscidea) three or four opening together in a single pore. In fig. 14 

 on PI. XVI. I figure a part of the integument of Colossendeis megalonyx magnified ; 

 in fig. 15 of the same plate a part of the integument of Colossendeis leptorhynchus is 

 shown. The glands seem to correspond with a wide vesicle (o), in the interior of which 

 a narrow canal (p) lies wound spirally ; this canal is easily traced till it opens at the 

 pore. Those conical cavities into which the glands are seen penetrating are much wider 

 than the others. For the structure of the gland itself the specimen of Colossendeis leptor- 

 hynchus which I investigated was not all I could have wished. On a transverse section it 

 looks quite as if all the original glandular cells had dropped from the connective tissue, 

 this tissue itself being the only part that remained as an empty skeleton. Perhaps the 

 state of preservation is to a certain extent the cause of this. The male specimen of 

 Colossendeis prohoscidea, in which also I studied these glands, was in a much better 

 condition. Plate XVIII. fig. 2 shows the distribution of the glands {g) over nearly 

 half the inner circumference of the skin of the fourth joint. Moreover, in fig. 3 a small 

 part of this skin is figured more strongly magnified with the glands opening into one of the 

 pores. The gland itself {g) shows a dense ball of round and nucleated glandular cells. A 

 comparatively wide and very transparent canal extends from the gland to the interior ot 

 one of the integumentary cavities (c), and a very narrow duct {d), which is irregularly 

 rolled up, runs through this wide canal till it reaches the pore at the end of the cavity. 

 When studying a part of the skin of the leg from the interior it is easily seen that three 

 or four of these glandular bodies send their ducts into the same integumentary cavity. 

 From the beautifully developed net- work of nerves and ganglionic plexuses, which extends 

 over the whole inner sm-face of the integument, distinct nerves are seen arising and 

 penetrating the cavities or innervating the glands. 



Finally, I wish still to mention the curious manner in which these glands of the 

 fourth joint of the male open in Oorhynchus aucklandice, Hoek. A very long 

 cylindrical appendage is inserted on the fourth joint a little behind the middle. The 

 gland opens at the tip of this appendage by means of a very long duct, which shows 



