NOTES ON RETieULARlAN RHIZOPODA. 35 



Genus — JACULELLA, nov. 



Jaculella acuta, n. sp. PI. Ill, figs. 12, 13. 



Characters. — Test elongate, straight or nearly so, closed 

 and pointed at one extremity, gradually increasing in width 

 towards the other, which, slightly constricted and rounded, 

 but otherwise open, forms the general aperture. Texture 

 arenaceous, very compact, and hard ; exterior surface rough, 

 interior also rough, but in a less degree. Colour rich brown 

 in the earlier portion of the test, becoming gradually lighter 

 towards the wide end. Length I inch (8*5 millim.). 



It is often an exceedingly difficult matter to determine 

 whether the tubular, non-septate, arenaceous tests, so fre- 

 quently met with in certain localities and in such diverse 

 forms, have belonged to sarcode animals or to annelids, and 

 there is unfortunately no character short of those pertaining 

 to the live inhabitant that can be regarded as certain evi- 

 dence. Annelid tubes of the commoner species are easily 

 recognised, and so also are the cylindrical tests of Rhizopoda 

 when they are either septate or labyrinthic, or show a dis- 

 tinct primordial chamber; but many of the specimens 

 alluded to, both arenaceous and porcellanous, present none 

 of these features, and the decision rests on probabilities 

 rather than positive indications. 



These remarks apply with some force to the species now 

 under consideration. The specimens were selected from a 

 number of doubtful organisms, as probably of Rhizopod 

 origin, on the strength of two or three characters which, 

 taken together, were tliought to have considerable weight. 

 The first of these was the firmly arenaceous texture of the 

 test, then the distribution of colouring matter which, as in 

 Hyperammi7ia vagans and several other species, is of deep 

 brown red in the early portions and gradually becomes 

 lighter, and, lastly, a fact of negative value, namely, that 

 the rough interior appeared ill-adapted for the organisation 

 and life conditions of an annelid. Not trusting my own 

 opinion on the matter, I submitted some of the tests to Dr. 

 Mcintosh, the recognised British authority on the Amielida, 

 who after examining them, expressed a very decided belief that 

 they did not belong to animals of that group. On the other 

 hand, there is no other non-septate type of Rhizopoda with a 

 test increasing so rapidly in diameter, and with an aperture 

 relatively so large; and, again, almost every specimen, if 

 not every one, has a minute orifice at the narrow end. The 



