814 RECORD OF CURRENT RESEARCHES RELATING TO 



head at the rounded end ; these were apparently part and parcel of 

 the sponge, both on account of their perfect condition and their 

 frequent occurrence in bundles, as if in nature. They proved, how- 

 ever, to be derived from a species of Esperia, common in the same 

 waters, and possessed of a peculiarly fragile spicular dermis, the size 

 of whose spicules agreed closely with those now found, and which had 

 no doubt parted with them with great readiness by the fracture of its 

 brittle covering. 



The second case was that of a species of Alehion, with spined 

 skeleton spicules ; besides other forms, among the bundles of short 

 skeleton spicules and in the superficial tissues, there occurred, singly 

 and in fasciculi, precisely the same spicula as those which intruded 

 into the Ciocalypta, and to almost as great an extent. In the former 

 case the close resemblance of the intruding to the skeleton spicules 

 offered great temptations for them to be assigned to the proper spicule 

 complement, whereas they were undoubtedly derived from the same 

 species of Esperia. 



In conclusion, the writer points out the need of careful observation 

 of the position and circumstances in which all spicules occur in any 

 sponges examined, as cases like the present are apt to occur in which 

 neither the broken or partially absorbed condition of these foreign 

 bodies, nor their markedly alien type, are present to point to their 

 real nature and prevent their ranking with the regular structures, and 

 perhaps assigning the sponge to a wrong genus. 



Protozoa. 

 Tentaculate, Suctorial, and Flagellate Infusoria.* — Prof. Ch. 

 Eobin first deals with Ophryodendron abietinum Claparede, Plate XVIII. 

 (Figs. 1, 2)."|' This species adheres to Sertularians, chiefly Sertularia 

 pumila ; it may be globular, ovoid, or discoid, is generally bilobate, 

 and has a long retractile tentacle (d), terminated by a bunch of mobile 

 cirrhi(e); its diameter is from -OG-'IS mm. It is strongly attached 

 by a short pedicle (a), which is often concealed by the application of 

 the whole lower surface of the body to the point of fixation. When 

 removed, the body may become globular. A groove (h) divides the 



* ' Journ. Anat. Physiol.' (Robin) xv. (1879) pp. 529-83, plates xxxix. to xhii. 



t Fig. 1. — Ophryodendi-on abietinum, separated by pressure from the Sertularia 

 to which it adhered, to show its point of adhesion, a, and the general form of the 

 body. 



6, i-)artially effaced furrow which divides the body ; c, point where the tentacle 

 springs from the body ; d, transverse folds of the retracted tentacle ; e, terminal 

 bunch formed of the cirrhi of the extremity of the tentacle. 



Fig. 2. — Ophryodendron after compression, the furrow having thereby dis- 

 appeared. 



o, d, e, as Fig. 1 ; c, Ii, i, a lobed gemmiform body ; /, worm or larva of parasitic 

 worm ; j, k, the hook by which it adheres. 



Fig. 3. — Acinetopsis rara Ch. R. a, pedicle ; 6, c, theca ; d, e, f, extensile and 

 retractile tentacle. 



Fig. 4. — Acineta patula Ehr., the body of which is suspended as it were in its 

 shell, which resembles a pedicellated cup. 



Fig. 5. — Aciyieta tuherosa Ehr., front view. /, the pedicle and its insertion at 

 the lower extremity of the body, e ; g, g, tubercles. 



Fig. 6. — Side view of the same. 



Fig. 7. — Trichodina Scorpenm Ch. R., side view, o, superior dorsal or con- 

 tractile portion of the body, often more or less contracted and flattened ; b, crown 



