der mannen Tricladen. 109 



largest of there species aiid for it 1 shall retaiii the name Bdelloura 

 Candida, followiiig the exaniple of V c r r i 1 1. Another species 

 which I propose to call Bdelloura propinqua, is about 8 mm long, 

 being about half as large as the full-grown B. Candida.'' (cf. Genus- 

 beschreibung). ,,When not otherwise staded the description of 

 the foUowing paper applies to this last species, to which 1 give the 

 specific name fellucidum " 



,,The appearence of S. 'pelluciduni, when resting fully extended 

 on a dark background, is reproducted in Fig. 2 nnder low magni- 

 fication. In the middle the sides of the body are parallel, bnt 

 towards either end they converge uniformly. The intestine shows 

 through the pellucid body-wall as a tlesh-colored mass. Anteriorly 

 the brain is easily seen as a pair of transparent swellings, which 

 form haloes around the two Black eyes. Other structures which 

 may be seen with a low power are the pharynx pairs and the two 

 rosette-like uteri. 



Like the species of Bdelloura, S. pellucidum is very active in 

 its movements, creeping with a steady, rapid motion over smooth 

 surfaces, or swimming at the surface of the water after the manner 

 of the fresh-water Triclads and Pulmonate Mollusca. Rapid 

 movements appear to be very common in the marine Triclads.". . . . 



,,Syncoelidium occurs only between the leaves of the gilbooks 

 of the Limulus, never migrating to the bases of the cephalothoracic 

 legs like the young and sexually immature Bdellourae." 



,,. . . Syncoelidimn prefers a small area near the edge and 

 just lateral to a small marginal callosity which forms a brown line 

 with the callosities of the adjacent leaves when the gill-book is 

 closed. 



The egg-capsule of Syncoelidimn (Fig. 5) is about. 75 mm long 

 of an oblong shape and somewhat compressed. It is attached 

 by a slender pedicel .5 mm in length, in such a way that one of 

 the flattened fsides of the capsule is applied to the surface of the 

 gill-leaf. Usually the capsules are arranged v/ith their long axes 

 parallel to one another in a little düster near the marginal callosity. 

 The chitinous wall of the capsule is thin and transparent, but 

 grows thicker tov/ards the poles. Through it the two opaque white 

 eggs or larvae may be distinctly seen. I have p.ever found more 

 than two eggs in a capsule." 



,,Syncoelidium oviposits in the latter part of July and the 

 early part of August, when the gills are deserted by the half- 

 grown young of B. Candida for the basal joints of the cephalo- 

 thoracic appendages. As the Limuli have laid their eggs and begin 

 to retum to deep water by the first days of July, it is necessary 

 in Order to study SynGoelidium and its habits, to collect a number 

 of the crabs early in the season and to contine them in a large 

 fish-box or similar receptacle." 



Die kurz gefaßte Speziesbeschreibung, die W h e e 1 c r zum Schluß 

 gibt, lautet: 



