1884. ] Zoölogy. 547 
tered nuclei, belonging partly to connective tissue, partly to gan- 
glion cells. The layer forms a continuous tube from the-head, 
where there is no ganglionic enlargement, back through the 
ra the caudal region, where the layer is present dorsally 
y. 
New AND REMARKABLE PENTASTOMUM IN THE AIR-SACS OF A 
Gutt.—P. Mégnin describes a new and remarkable Pentastomum 
found in the air-sacs of Larus glaucus. About six centimeters 
long and one broad, it has at first sight the appearance of a Tre- 
matode; but a microscopic examination reveals the presence of 
two pairs of symmetrically placed hooks at the anterior end. The 
new species is remarkable for the attenuated form of the anterior 
extremity, and the absence of any external annulation. At the 
front end there are two tubercles which look like aborted antennæ, 
and below there is an indication of a kind of segment. 
On what may be regarded as the second ring there is a pair of 
small appendages, formed of two joints, which call to mind the 
characters of larval Pentastomes, The characters of these new 
species resemble greatly those of the Lernzidz, and especially of 
the Chondracanthidz, and seem to M. Mégnin to raise the ques- 
on of the systematic affinities of these parasites. If the resem- 
€ to the Lernzidz is a real one, the Pentastomide should 
ranged rather with the Crustacea than with the Arachnida. 
Tue Sipz ORGANS or Gastrostomus—Mr. J. A. Ryder com- 
Municates to Science a description and sketches of the curious 
nculated organs of the lateral line of Gastrostomus. These 
nè prend in groups of from two to five, forming an oblique row 
hinder margin of each muscular somite. The stalks are 
aa Miliy a sixteenth of an inch long, and project outwards 
the ti reeiy when the fish is immersed in alcohol or water. At 
whi P of each is a discoidal, more or less cup-shaped organ, 
is deepl i less dense than that of the surrounding skin, which 
disks is’ aae ed with black. The pigmented layer of the basal 
the Meda uous with the outer clear sheaths of the stalks, and 
Consist 
| ited. ‘cing water; but no larval fish as yet known has peduncu- 
35 
