Mr. C. Spence Bate on Crustacea amphipoda. 361 



ing vessels, after penetrating through the pericarpial envelopes, 

 suddenly expands into a broad fleshy sheath, in the tissues of 

 which the cord of the raphe is continued till it terminates in the 

 chalazal point of the partly-formed seed : this very elongated 

 sheath is coiled round in a spiral form, and near its extremity 

 there is seen a very deep groove, which terminates in the small 

 open mouth of an oblong pouch, which is a continuation 

 of the sheath, and in which the ovary with its closed tunics 

 is affixed at its base. In this instance, the flower had long 

 before withered, and the ovary had grown to a considerable 

 size, being now above 3 lines in length. Here we have proof 

 of the peculiar nature of the long placentary sheath, and of 

 its pouch-like development : the perfect resemblance of the 

 latter to the analogous pouch above described, as seen by me 

 in the ovule of the Almond, is convincing ; and p- 3 

 we have here evidence that this pouch can in no 

 way be considered as one of the original tunics of 

 the ovule, and therefore cannot be held to be the 

 primine. I annex the figure of another very instruct- 

 ive example (fig. 3), observed in an abortive ovule 

 of a species of Drimopus, the whole of which being 

 transparent, affords a proof of the real structure : 

 here the placentary sheath is straight, and sus- 

 pended from near the summit of the cell ; its lower 

 portion is grooved, and the margins of this groove 

 terminate in the open mouth of an oblong sac, 

 which is an extension of the sheath, similar to that 

 seen in Pistacia. We observe at the base of the 

 included nucleus, which is also surrounded by its 

 two open tunics, the common point of their at- 

 tachment to the bottom of the pouch, in which 

 point we see the termination of the raphe, which 

 thence is traced along the sheath to the place of its 

 origin in the placenta. 



XXXV. — On some new Genera and Species 0/ Crustacea amphi- 

 poda. By C. Spence Bate, F.L.S. &c. 



Among the Edriophthalmous Crustacea belonging to the Collec- 

 tion of the Royal College of Surgeons, which have been entrusted 

 to me for examination, the following appear hitherto to have 

 escaped being described. 



Macrocephalus, n. g. 

 Cephalon horizontaliter porrectum. Antennae inferiores nuUse. 



