398 



SCIENCE. 



[N. S. Vol. VIII. No. 195. 



pathetic system and sense organs were de- 

 scribed ; the latter consist of cells contain- 

 ing a pear-shaped refractive bodj', also com- 

 pound bodies similar to the eyes found in 

 other worms. 



A New Classification of Fossil Cephaloj)ods. 



By Professor Alpheus Hyatt. 



Cephalopods with camerate shells, ex- 

 cluding Belemnoidea, are included in two 

 orders, ISTautiloidea and Ammonoidea. The 

 classification of the Nautiloidea is in con- 

 fusion, owing to the overthrow of the old 

 systems. After revising all the genera and 

 a considerable proportion of the species of 

 this group it was found that the siphuncle 

 offered the best basis for a classification. 

 The siphuncle was of greater importance 

 in ancient than in more recent times, in 

 primitive than in specialized forms, and in 

 the young than in later stages of ontogeny. 

 This assumption is based on the relatively 

 larger size, and more or less complicated 

 structure of this organ, in ancient times, 

 primitive types, and the young of all 

 shells. Proposed sub-orders of Nautiloidea 

 are as follows : 



1. Holohoanites, funnels of siphuncle 

 extending across air-chamber, deposits 

 when present, more or less prolonged cones, 

 filling endosiphuncle. Endoceras, Piloceras, 

 Nanno. 



2. Mixochoanites, siphuncles small, fun- 

 nels composite, short in young, collars 

 added in adult. Ascoeeras, Aphragmites. 



3. Schistochoanites, siphuncles large, fun- 

 nels imperfect or split on outer side ; these 

 are at bases of flat rings or collars. Couo- 

 ceras, Bronn (Bathmoceras, Barr). 



4. Orthochoanites, siphuncles small, ex- 

 cept in primitive forms, without deposits, or, 

 if present, irregular and gathered around 

 funnels, no endosiphuncle. Is difficult to 

 separate some forms of this suborder from 

 the Annulosiphonata. Orthoceras, Geisono- 

 ceras. 



5. Cystochoanites, siphuncles of different 

 sizes, funnels invariably short, bent out- 

 wardly. There are two subgroups. (A) 

 Annulosiphonata, siphuncles large in primi- 

 tive forms, beaded, internal deposits gath- 

 ered about the funnels. There also are 

 concentric layers advancing toward the in- 

 terior, large endosiphuncle often present in 

 primitive forms. Actinoceras, Loxoceras. 

 (B) Actinosiphonata, internal deposits ar- 

 ranged as vertical radiating plates, directed 

 toward interior, but not meeting; deposits 

 increase in number of plates and thickness, 

 so they often meet those of next segments. 

 Jovellania, Eizoceras. 



On the Systematic Position of the Trilohites. By 



Professor A. S. Packard. 



Beecher has shown that all segments 

 behind the antennal bear biramose limbs 

 essentially alike for the head and trunk. 

 In Crustacea, on the other hand, there is a 

 differentiation of cephalic appendages. For 

 this reason, with the different larval form, 

 and obvious affinities of trilobites to Limu- 

 lus which is not a Crustacean, we are in- 

 clined to refer trilobites to a separate class, 

 older, more primitive, derived from the 

 annelids on a different line from Crustacea. 

 Probably the merostomes, including Limu- 

 lus, descended from trilobites or similar 

 forms. 



Measurements of two large Lobsters, recently 

 added to the Collections of the American 

 Museum of Natural History. By Dr. E. 0. 

 Hovey. 



Two large lobsters were caught off At- 

 lantic Highlands, N. J., in 1897. Reported 

 weight 31 and 34 pounds respectively. The 

 length as mounted is respectively 92 cm. 

 and 100.5 cm., or over 3 feet in each case. 



A New Method of Studying Underground In- 

 sects. By Professor John B. Smith. 

 Shown that plaster of Paris, thinned, 



made excellent casts of burrows extending 



