REPORT ON THE CRUSTACEA MACRUKA. 515 



& 



The posterior pair of pleopoda is long, reaching almost to the extremity of the long 

 slender telson ; the external ramus is strengthened on the outer side by a thick 

 margin which terminates in a sharp tooth, coinciding with the outer extremity of an 

 imperfect diaeresis that extends halfway across the plate, and is distant from the 

 extremity about one-fourth the length of the appendage, from which point it is fringed 

 with long ciliated hairs round the extremity and inner margin. The inner ramus is 

 about the same length as the outer, terminates in an obtuse point, and is fringed on both 

 sides with long ciliated hairs. 



The female bears about thirty or forty ova, in which the embryo in our type specimen 

 is seen to be approaching the stage of extrusion, a circumstance that enabled me. 

 but with some difficulty, to approximately determine the form of the brephalos. 



The ovum is oval in form and supported by a membranous filament attached to 

 the hairs of the basal joint of the pleopoda, none being attached to those on the 

 branches. 



The brephalos (PI. XCII. fig. 4) is very unlike that of the genus Crangon, as observed 

 in the typical species Crangon vulgaris (PL LXXXVI. fig. 4). It approximates more 

 nearly to that which I have seen in Crangon boreas, Phipps, and bears a close relation 

 to that of Homarus vulgaris, the common European lobster. The brephalos of Glypho- 

 crangon is in the Megalopa stage, and the absence of the chelate condition of the 

 pereiopoda is probably due to the early stage at which the embryo was examined, for 

 the young must quit the ovum in a very matured condition, since the vitellus was still 

 large at the period when I had the opportunity of examining it, consequently some time 

 would elapse before the embryo would be mature enough to become independent, 

 but even in this immature condition every appendage is present in a more or less 

 advanced condition. 



The ophthalmopoda are spherical, and if not small, are certainly not large ; the first 

 pair of antennae is considerably advanced in growth, terminating in a point, tipped with 

 one or two cilia, and supported by a small pointed lobe which I take to be the extremity 

 of the peduncle. The second pair of antennas has a large scale-like appendage (the 

 scaphocerite), the sides of which are nearly parallel and the extremity oblique, rising to 

 an obtuse point, and a flagelliform appendage that already reaches beyond the extremity 

 of the scaphocerite. 



The oral appendages are apparent, but not easily determinable as to their exact form 

 in this immature condition, until we reach the second and third pairs of siagnopoda, the 

 former of which resembles generally that of the adult, and the latter forms an unequally 

 biramose appendage of the same type as that of the two pairs of gnathopoda next 

 succeeding, which lessen the inequality of their branches as they advance posteriorly. 

 The several pairs of pereiopoda are in an advanced stage of development, and each 

 carries a secondary branch. 



