36 SUMMARY OF CURRENT RESEARCHES RELATING TO 
himself justified in naming a new species which he calls P. Diogenes ; 
it lives in depths of from 350 to 1500 metres ; the characters by which 
it differs from the well-known species are carefully pointed out in detail. 
Three specimens were found of the rare Rhabdosoma armatum. Oxg- 
cephalus piscator and 0, tijplioides were found to be commensals of 
Eucharis multicornis. 
A description is given of a remarkable new Amphipod, called Fortu- 
nata lepisma, which it is somewhat difficult to associate with any of the 
known families. It agrees with the Gammaridae in the small size of the 
eye and of the cephalic segment, while the want of a lateral compression 
of the body and the form of the segmental appendages calls to mind 
some of the Hyperina. Milne-Edwards rightly insisted on the value of 
the form of the antenna as a characteristic of the latter group ; of these, 
the Phronimida, like Fortunata, have the anterior antennas two-jointed, 
while the hinder antennas are absent in the female. On the whole, 
however, the characters of this new form are sufficiently peculiar to 
justify the formation of a new fiimily — that of the Fortunatae — for its 
reception. The author adds a diagnosis of the family. 
In the Atlantic, as in the Mediterranean, the Schizopoda form a very 
characteristic part of the pelagic fiuina. The remarkable Euchsetomera 
typica, described by G. O. Sars in the ‘Challenger’ Eeport, is now for 
the first time definitely stated to inhabit the Atlantic. By the 
astounding length of its upper antennas, which were broken off in the 
Pacific Ocean specimens obtained by the ‘ Challenger,’ by the size of 
its endopodites, the remarkable shortening of the carapace and telson, 
this form is characteristically intermediate between Mysis and the 
Araclinomysis Leuclcartii which the author lias described from the depths 
of the Mediterranean. Sfylocheiron mastigaphoriim, first found in the 
Mediterranean, was found at all depths. S chelifer sp. n. is so called 
on account of the size of its chelae ; its antennae are as long as its body. 
Sergestes sanguineus sp. n. is so called on account of the blood-red 
coloration of its astonishingly long lower antennae, which are more 
than four times as long as the body ; it is distinguished from all the 
Sergestidae yet described by the extraordinary development of its 
penultimate thoracic legs. 
Differences in Developmental History of Marine and Freshwater 
Forms of Palsemonetes varians. * — Dr. J. E. V. Boas points out that 
the species hitherto known as Palsemonetes varians contains two forms ; 
one, northern and marine or brackish in habitat, the other more 
southerly in distribution and a dweller in fresh water. The adults 
are so like one another that there could be no reason for separating 
them specifically, but their developmental history is very different. The 
egg of the freshwater form has eight times the volume of the marine ; 
the latter leaves the egg as a gill-less zoea, passes through a normal 
Mysis-stage, and takes food from its birth. The freshwater form 
appears as a much better developed zoea, and has gills ; the exopodites 
of the thoracic feet are only slightly developed, so that there is only an 
indication of the Mysis-stage — i. e. there is an abbreviation of the meta- 
morphosis ; and in consequence of the large quantity of the nutrient 
* Zool. Jahrb., iv. (1889) pp. 793-805 (1 pi). 
