ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
179 
Externally to' this there is in the brain an inclosing membrane which 
the author compares with the “ Glyahiille ” described by Gierke in the 
Vertebrata, and which may be regarded as a product of the outermost 
parts of the perineural neuroglial plexus. In the ventral medulla this 
membrane is only found in the dorsal region. 
In Lumbricus the neuroglial envelope does not send processes into 
the central nervous plexus, and there is not, therefore, a neuroglial 
plexus in the central nervous system as there is in the free Polychfeta. 
In Sipunculus there is an outer and an inner neuroglial plexus, but there 
is no glial plexus in the central fibrous substance; in this point the 
Sipunculaceae differ from the free and resemble the tubicolous Polychaeta. 
The wide-meshed plexus of the Nemertinea is not identical with the 
neuroglia of other worms, which neuroglia is merely represented by a 
membrane which lies between it and the ganglionic cells. In Cere- 
hratulus the neuroglia is in a very primitive condition. 
o. Annelida. 
New Pelagic Annelids.* — Herr G. M. E. Levinsen has established 
a new genus Corynocephalus in the family Alciopidae. The body has 
few segments ; the head-lobe is subdisciform in front, convex above, and 
furnished with four leaf-like antennae ; the dorsal cirri are also leaf-like, 
large, and imbricate ; the parapodia have no cirriform processes on their 
apices ; the setae are mostly simple and hair-like, mixed with some of a 
rougher and more rigid type ; the ventral papillae are depressed at the 
base of the parapodia ; the segmental organs are small and somewhat 
dorsal. This genus includes C. albomaculatus sp. n. from the South 
Atlantic. Another new species described is Mliynchonerella longissima. 
In a new family Typhloscolecidae Uljanin, near the Opheliidae, the 
author places Travisiopsis g. n., with T. lobifera sp. n. In the new 
family there are two segments in front of the mouth. Of these the first 
has an unpaired antenna, and the second (as well as the two next 
segments) a single nodiform “ parapodium,” which is not, however, 
comparable with the ordinary structure known by that name. The 
other parapodia are disposed in a double row on each side. The nodi- 
form “ parapodia ” are drawn out into leaves containing fascicles of little 
rods and without setae. Simple, acicular setae (2-3) are borne on the 
segments with biserial parapodia, between the dorsal and ventral series. 
Above the pharynx is a blind protractile proboscis. The geographical 
distribution of Sagitta is also discussed. 
British Species of Pachydrilus.f — Mr. F. E. Beddard thinks that 
two species of Pachydrilus are to be found at Rum Bay. One of these, 
which is much larger than the other, appears to be P. verrucosus of 
Claparede, while the other does not seem to be a representative of any 
of the other four British species described by that author, but to be 
P. nervosus of Micbaelsen ; this is the only form in which the peculiar 
perivisceral corpuscles which are so characteristic of these worms do 
not appear to be present. 
The present state of our knowledge regarding the male gonads and 
* Spolia Atlantica, K. Danske Vicl. Selsk., iii. (1885) pp. 327-44 (1 pi.)* 
t I’roc. Roy. Tliys. vSoc. Edinb., x. (1889) pp. 101-6 (1 pi.). 
N 2 
