1060 General Notes. [ December, 
outer surface under the epithelium of a pedunculated club-shaped 
body e. g., Lucina lactea. The view that the byssus of the 
lamellibranchs is homologous with the gastropod operculum is 
rejected on anatomical and histological grounds, and the muci- 
parous byssiparous glands are thought to correspond with the 
“ Lippen-drüsen ” and “ Fusshohledriisen” of Carriere, the one 
upon the fore-end of the gastropod foot, the other upon the creep- 
ing surface. 
The second portion of the work is a full historical and critical 
review of the “water-pore” controversy. No new observations 
of importance are recorded and the position maintained by the 
writer is the same as already represented in this journal (see Vol. 
Ill, p. 130).—Henry Leslie Osborn, Purdue Univ., Lafayette, Ind. 
ON THE CLASS PODOSTOMATA, A GROUP EMBRACING THE MEROSTO- 
MATA AND TRILOBITES.—In a paper read before the National Acad. 
of Sciences we have endeavored, by giving the history of the 
Xiphosura, Peecilopoda and Gigantostraca, to show that while 
the name Xiphosura should be retained for the suborder of which 
Limulus is the type, the names Pwcilupoda and Gigantostraca 
have been applied in such different senses, that they can not well 
be retained for the Merostomata and Trilobita taken together in 
the sense we advocate. We have therefore proposed the term 
Podostomata for this class of Arthropoda. It is derived from 
zoc, zodds, foot; and stéua, mouth, in allusion to the feet-like or 
ambulatory nature of the cephalic appendages which surround the 
mouth in a manner characteristic of the group. 
The class Podostomata may be defined as a group of marine 
arthropods in which the cephalic (Limulus) or cephalothoracic 
(trilobites) appendages are in the form of legs, z. e., ambulatory 
appendages, usually ending in forceps or larger claws (chele), 
which in the sole living representative of the class are arranged 
in an incomplete circle around the mouth; the basal joint of each 
leg is spiny, so as to aid in the retention and partial mastica- 
tion of the food. No functional antennz, mandibles or maxillz. 
Eyes both compound and simple. Respiration by branchia at- 
tached to the abdominal appendages which are broad and lamel- 
late in Merostomata, and cylindrical with narrow gills in Trilo- 
bita, The brain supplying nerves to the eyes alone; the nerves 
_ to the cephalic or cephalothoracic appendages originating from 
an cesophageal ring; the ventral cord enshea y a ventra 
arterial system more perfectly developed than in insects or scor- 
pions; coxal glands highly developed; with no external opening 
im the adult. The class differs from the Arachnida, among other 
characters, in having no functional cheliceres (“ mandibles”) or 
pedipalps (“maxillae”); in the cephalic appendages either ending 
_ in larger claws or forceps, or in being simple, the terminal joint 
_ not bearing a pair of minute claws or ungues like those of Arach- 
