116 Zoological Collections. In vertebra ta. 



pursued ; we must scrutinize, analyse, and dissect, in order to determine the 

 number, use, and structure of the various members. 



Dr Leach being the founder of this genus, the first crustaceologist in 

 Europe, and of the most scrupulous exactness, we must naturally attach the 

 greatest importance to the figure and description of Nebalia which we have 

 from his hands, bearing in mind that the parts of the mouth remain to be 

 dissected and made known. 



Description of the Nebalia. — The cephalo-thoracic clt/petcs, enclosing the 

 body of the animal, is large, sub-compressed, and ovalish in its lateral 

 contour. 



The movable rostrum or beak, which is one of the most remarkable 

 characters of Nebalia, is taper, carinated above, and vaulted beneath. 



The eyes are rather small, and situated at the sides of the beak ; they are 

 compound, placed on short footstalks, and movable. ' ^ ' ' 



The antenncB, which arise on each side from above the eyes, coflsisfe of a 

 single pair, each ending in two pluri-articulate setae. '*' -^j' 'i^ o'ijijniixo! , 



The anterior pair of feet are long and simple, serving' fo:^^t3ieri^ifti,>(J«n[d 

 are probably armed with microscopic hooks?) ; • >^^'^f^ '■ ■ '" " " 



The posterior or natatory feet consist of fivei I^Sfe ^Ving their ultimate 

 divisions bifid and fringed. ''"■ '"'''^ If j.. ^ 



The abdominal portion is composed of four or five joints, •*rti9*%'ftfiB*hfit'a 



furcate tail, the two taper styles of which end in setse. 



1,3, a 



The Nebalia Herbstii of Dr Leach attains to the length of three-fourths 

 of an inch, and is of a pale red or greenish colour, (grayish. Leach,) with black 

 eyes, and inhabits sandy shores about Greenland, and particularly the mouths 

 of rivers, but is rare. According to Dr Leach, it is also found in the 

 European Ocean. The female, Fabricius says, carries her ova all ^vinter, 

 which begin to develope themselves in April ; the young appear in May, are 

 extremely active, adhere to the mother, which has then but little life. In 

 swimming, they turn on the back, and use their hinder feet, and when they 

 rest, fx thetnselves by the anterior pair ! 



The Nebalia Montagui, which Montagu describes under the title of 

 Monoculus rostratus, is only half the size of the former species, viz. 

 three-eighths of an inch ; is of a pale yellow colour, with a darker longitu- 

 dinal line along each side ; inhabits the south coast of Devon. The fore 

 feet, he adds, are usually motionless and brought down under the body ; and 

 that the antennae, as well as the natatory feet, are continually in movement 

 when the animal swims. 



I beg to repeat, that we know these little animals too imperfectly, and that 

 they present a field for future observers, who may happen to be so fortunate 

 as to meet with them. We must see them reversed ; the organs of the 

 mouth and members developed and magnified, which, in an animal of such 

 size, cannot be considered as a very difiicult task, when we contemplate what 

 has been performed on many of the smaller Monoculi not one-third part so 

 large as the smaller Nebalia. In addition, it would be desirable to know 

 whether they are really perfect animals, or only larvae, determinable by keep- 

 ing some of the full-grown ones in sea water, frequently renewed, or by the 

 actual discovery of females provided with ova. 



Description of a fragment of an unknown Molluscum, supposed to be the Animal 

 of the Nautilus pompilius, Linn. By MM. Quoy and Gaymard. 

 We found in the Moluccas, near the Island of Celebes, a portion of an 

 animal, above eighteen inches long, and of a proportionate breadth, evidently 

 belonging to the Cephalopodous moUusca, and which we suspected to be a 

 fragment of Nautilus pompilius. It had a large coloured portion, which would 



