of Edinburgh , Session 1881-82. 
697 
cross or star, composed of four long, straight arms with the ends 
more or less enlarged, flattened and pierced with one large and a few 
small holes ; sometimes the enlarged ends of the arms are connected 
with one another, forming a more or less round, perforated plate ; 
the centre of the cross always with a large and straight tower or 
steeple, directed outwards from the body of the animal, and composed 
of four long, straight, parallel columns, held together by three to 
seven transverse bands. The pedicels and processes with numerous 
rather large, more or less arcuate spinous spicula, and the former with 
a rudimental perforated terminal plate. 
Only one pyriform sac, rather slender and cylindrical, the length 
being about 35 mm. The madreporic canal dorsal, very small, with 
numerous small spicula, curved in the form of a C, and resembling 
those of the integument. Each of the powerful longitudinal muscles 
is double. Genital tubes dichotomously branched, arranged in two 
rather large clusters, one on each side of the dorsal mesenterium, 
each cluster being again divided into from five to seven smaller ones. 
The respiratory trees (if they really belong to these animals) are two, 
undivided, almost of equal size, about 45 mm. in length, and bearing 
along their whole length a great many small processes or branches. 
Colour in alcohol light grey ; terminal parts of the tentacles yellowish 
with some dark points. 
Report on Echinoidea. By Professor Alex. Agassiz. 
I have examined the things and send you a list. There is nothing 
new, but I am very glad to have good specimens of Phormosoma 
uranus and placenta , which I had not seen, as well as good young 
specimens of Echinocardium pennatifidum , which are interesting. 
Doroddaris papillata, A. Ag. 
St. 1 
305 fms. 
Poroddaris purpurata, W. Th. 
St. 7 
530 
3 3 
Phormosoma uranus, W. Th. 
St. 4 
555 
33 
,, placenta, W. Th. 
St. 4 
555 
3 3 
and St. 2 
530 
33 
Echinus norvegicus, D. & K. 
St. 7 
530 
3 3 
St. 1 
305 
3 3 
St. 3 
53 
3 3 
,, acutus, Lamk. 
St. 3 
53 
33 
, , melo, Lamk. 
St. 3 
53 
3 3 
Ecliinocyamus pusillus , Gray 
St. 3 
53 
3 3 
