Jan. 25, 1872J 



NATURE 



255 



to the chilaria and to the opercular plate limbs. The neural axis 

 then continues, as a pair of coalesced chords, to the middle of 

 the thoracetron, developing five ganglions supplying the five gill- 

 limbs. Beyond the fifth ganglion the chords separate ; each 

 forms a loop resembling a ganglion, beyond which each chord 

 penetrates the base of the "pleon." To this it supplies five 

 dorsal and five ventral nerves before being continued and resolved 

 into a plexus toward the end of the tail and spine. The author 

 remarked that, as the nervous system preceded the tegumentary 

 in the order of development, it might thus manifest evidences of 

 the more generalised segmental type of the pleon, more plainly 

 than had been noticed in the formation of the chilinous walls of 

 that division of the body, in the embryo, in which it first budded 

 forth as a ninth segment of the thoracetron. Details of the 

 organs of the senses, of the digestive, circulatory, respi- 

 ratory, and generative systems were then given, and illustrated, 

 like the nervoas system, by minutely-finished drawings. The 

 heart was elongate, vasiform, included in a pericardial-like 

 sinus : besides an anterior and posterior aortic trunk, there were 

 seven pairs of lateral primary branches. The arteries soon lose their 

 tubular form, and , as they e.xpanri , lose like wise much of their fibrous 

 wails, and seem reduced to delicate membranous sinuses whicli 

 follow the shapes of the parts or interstices along which the blood 

 meanders as it returns by the venous sinuses to the general peri- 

 cardial one. The most remarkable of the arterial prolongations 

 are those which the author had previously described in his 

 "Lectures on Invertebrata " (8vo ed., 1S55, p. 310) as expand- 

 ing upon, and seeming to form the neurilemma of, the central 

 axis and branches of the nervous system ; so that injection of the 

 anterior aorta coats the neurine and demonstrates a great part of 

 the nervous system by its colour. (A drawing showmg this effect 

 of fine red injection was exhibited. ) Finally the author cited 

 the chief results of the observations of Lockyer, Packard, 

 and Dohrn on the development of the king-crab. There 

 was neither a nauplius stage nor a trilobite stage. A super- 

 ficial resemblance to trilobites is shown by the absence of 

 the pleon iu the embryo king-crab ; but the very fact of the 

 late appearance of this terminal division was decisive 

 against any reJ representative resemblance of the embiyo 

 Limulus to the trilobites ; on the acceptance, at least, of Bar- 

 rande's observations of the successive and later appearance of 

 the segments of the "thoracetron" in the space between the 

 head (" cephaletron ") and "pygidium " (pleon and tail-spine) 

 of the embryos of Sao, Agiwstus, and Trinucleus. The author here 

 recalled attention to Newport's observations of the hke develop- 

 ment of successive segments, anterior to the caudal one, in 

 lulidas, and remarked that with otlier facts noted in the anato- 

 mical sections, especially the fusion of the pair of cephalic 

 ganglia, and the short and thick crura connecting these with 

 the subresophageal mas=, giving the condition of that part of the 

 nervous system in Storpio and lulus, Limulus manifested in an 

 instructive and interesting way the more "generalised type" of 

 articulate structure, in which arachnidan and myriapodal charac- 

 ters were associated with crustaceous ones. But, in the develop- 

 ment of Limulus, the pleon, pygidium, or tail-spine was the last 

 to appear, and, at its first buddmg, looked like a ninth segment 

 of the thoracetron. Packard speaks of indications, transitory 

 indeed, of segmentation of the crust ; and such indications, as 

 the author had shown in the anatomy of Limulus, were more 

 strongly and lastingly given by the nervous system. The 

 tail-spine belongs to the series of body-segments, and is 

 no mere appendage to the dorsal arc of such. After 

 formifaction and the attractive and repellent forces have 

 produced in the germ-masses the phenomena of segmentation 

 and vegetative repetition, as mmifested in the similar and 

 parallel heaps of granules, like bricks for the building, the in- 

 herited influences overrule the polaric ones, and operate in 

 diflTerentialing and adaptive lines, speedily showing the embryo 

 Limulus, which, like \.\viXo{ Astiuusfluvialilis, Palcrmouadspcisus, 

 Craiigciu niaculosus, Eriphia spinij'rons, and one may add, all 

 Cephalopods, takes its own course to the full manifestation of its 

 specific characters, agreeably with the nature originally impressed 

 on the germ. There was no divergence to a larval form with a 

 term of active life as such ; there was no metamorphosis, either 

 "nauplial" or " trilobitic." Some objected to the king-crabs 

 bfing called Crustacea ; there was more ground, the author 

 thought, for objecting to call them Arachnida or Myriapoda. 

 Characters common to Limulus with their allied extinct gill- 

 bearing, well limbed Articulata, have not a class- value. The 

 author could not, at least, raise the Merostomes to an equivalency 

 with, and run them paraUel to and alongside of, the rest of the 



branchiate Condylopods. A class, after all, was an artificial 

 group, a help to the classifier. One may call Limulus a Crus- 

 tacean and yet discern in its anatomy the evidence of its more 

 "generalised structure' than in Malacostraca ; its type preceded 

 that of either macrourous or brachyurous Crustacea, and indicates 

 characters subsequently appropriated by and intensified in the air- 

 breathing members of the Apterous Insecta of Linnceus. As com- 

 pared with its longer-bodied and many-jointed predecessors, Z/- 

 w;«/;w itself shows a concentrative specialisation; but vegetative 

 repetition still reigns in the limb-series. " Inner antennules," 

 "outer antenna;," "mandibles," "maxilla:, ""maxillipeds," "legs," 

 all work togetherby their basal jointsin subserviency to mastication, 

 and all end in pincers. As compared witlimodern crabs no structure 

 was more striking and significant than the resistance, so to speak, 

 of the heart in Limulus to the concentrative tendencies ; it is 

 still the "dorsal vessel," though the body-part containing it has 

 the breadth and shortness ot the crab's carapace, in which the 

 heart is shaped to match. In both the neural axis supplying the 

 cephaletral limbs is annular, but in modern crabs the subceso- 

 phageal part is defined by distance and concomitantly long 

 and slender from the super-cesophageal or cerebral part. This 

 differentiition had not taken place in Bellimuyus, Ncolimulus 

 Pi-cshmchia, and other palaeozoic predecessors of Byachvuva, 

 whose organisation we have to thank their long-lived, Imgering 

 representative genus for enabling us to peer into. 'That such 

 glimpses, vrith concomitant tracing of the development of the 

 individual Limulus, afford us some ground, and that the like 

 work, with persevering quest of its pateozoic fossil allies, may 

 afford more, tor guessing at the ways in which a pre ordained 

 plan of derivation by congenital departures from parental form 

 has operated, in originating the various deviations from a com- 

 mon primitive articulate type, is an encouraging faith. That the 

 old ocean should have given the chance conditions of origin of 

 custaceous sub-classes, orders, genera, species, by natural se- 

 lection, was not conceivable by the author, who, nevertheless, 

 held the conviction that all forms and grades of Articulata were 

 due to " secondary cause or law," as strongly as when he ex- 

 pressed the same conclusion in regard to the Vertebrata, and 

 termed it "the deep and pregnant principle" evolved in the re- 

 searches on the general homologies and archetype of their skele- 

 tons. 



Mathematical Society, January 11. — Mr. W. Spottiswoode, 

 F.R.S., president, and subsequently Prof Cayley, V.P., in the 

 c>iair. MajorE Close, R. A., was admitted into the society. Prof. 

 Cayley gave an account of his paper " On the Surfaces the loci 

 of the Vertices of Cones which satisfy six conditions." — Mr. J. 

 W. L. Glaisher stated and illustrated the principal points in his 

 communication " On the Constants which occur in certain 

 summations by Bernouilli's Series. — Mr. W. B. Davis read a 

 paper describing the methods he had used in the construction of 

 tables of divisors, and exhibited tables of factors of numbers 

 consisting of nine and twelve figures. A brief discussion ensued 

 on the subject of this communication- — Mr. Roberts explained 

 some of the results which he submitted to the society in his paper 

 " On the parallel surface of Conicoids and Conies," and illustrated 

 the same by means of a model and drawings of sections of one 

 of the surfaces. 



Zoological Society, January 16. — Prof. Newton, F.R.S., 

 vice-president, in the chair. — The Secretary read a report on the 

 additions that had been made to the Society's collection during 

 the month of December, 1871, amongst which was particularly 

 mentioned a young Prince Alfred's Deer (Cuiius alfriJi), born 

 in the Gardens, — A le'ter was read from Prof Owen, F.R.S., 

 communicating some particulars received from Dr. Julius Haast, 

 of Christchurch, New Zealand, respecting the finding of the 

 remains of Aptornis in the Glenraark Swamp, New Zealand. — 

 Mr. H. E. Dresser exhibited and made remarks on specimens of 

 the eggs oi Rcguloides supercilicsus and ReguloiJcs ociipitatis, col- 

 lected by Mr. W. E. Brooks in Cashmere. — A communication 

 was read from Dr. G. Hartlaub and Dr. O. Finsch, giving an 

 account of a collection of birds from the Pelew and Mackenzie 

 Islands in the Pacific, to which was added a complete synopsis 

 of the ornithology of this pordon of the Caroline group. — A 

 communication was received from Mr. A. Sanders, containing a 

 complete description of the Myology o( Liolcpis belli. — Mr. A. G. 

 Butler communica'ed a synomic list of the species formerly in- 

 cluded in the genus Picris, with references to all others described 

 since the subdivisions of that genus by recent authors. — A com- 

 munication was read from Mr. John Brazier, of Sydney, N.S.W., 

 giving a list of the Cyp)-cciz met with on the coast of New 



