This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1884 edition. Excerpt: ...1862, p. 149, Annulosa, pi. 15, fig. 7); but the Cypridinal notch is absent in the latter, and the Musclespot is very different. Pigs. 1 and 7 of our Plate I have outlines somewhat similar to that of Polycope orbicularis, Brady (' Lin. Soc. Trans., ' vol. xxvi, pi. 35, fig. 53); but with this the resemblance ends, for in Polycope the Cypridinal notch is quite obsolete. With the similarly globose, but strongly hinged, Heterodesmus an imperfectly known Cypridinad from the Sea of Japan, Entomoconchus has shape and gibbosity in common, but the hingements differ, as well as the form and amount of notch or sinus. Judging by the carapace-valves, all of the animal that remains to us, Erttomoconchus was a marine gregarious Bivalved Entomostracan (as indicated by M'Coy in 1839), closely allied to the existing Cypridinadce; but the high position and the feeble development of its "notch " and "hood," and the vertical, narrow, interrupted anterior "gape" of the valves, are distinctive features, connected with the extrusion of the antennae (swimming limbs) and other organs, which were doubtlessly planned somewhat differently to those of the existing genera. For the better understanding of the illustrations referred to we note that--In Prof. M'Coy's figures (1839)--Fig. a is the anterior aspect of a carapace, the dorsal border being to the right hand of the reader, and the right valve upwards. Compare our PI. I, fig. 2 d, &c. Fig. b is the ventral aspect, with the anterior end upward. Compare our fig. 6 c, &c. Fig. c is the side view of a carapace, showing the right valve and its muscle-spot; the anterior end is upwards, and the dorsal border to the left of the reader. Compare our fig. 4 a, &c. Fig. d (natural...